We hadn't seen A for several months and were shocked at his appearance. His once-robust, muscular build had disappeared, and his clothes hung on his wasted frame. This man who had been an expert skier on snow and water, who routinely ran several miles a day even after he turned 80, and worked out in a home gym daily, he now seemed to be only skin and bones. What happened? Months of physical inactivity due to his care of his terminally-ill wife had eliminated his time and desire to exercise. The effect was drastic loss of muscle mass and strength. Indeed, it was painful to watch him attempt to stand up from a chair without using his hands to push himself upright. Our friend was frail and probably was suffering from sarcopenia.
Sarcopenia refers to the disappearance or wasting of muscle, just as osteoporosis refers to the wasting or loss of bone. And, like osteoporosis, the decline in muscle mass and strength begins once we enter the sixth decade of life, although poor diet and inactivity may start both processes decades sooner. The loss of muscle is not as obvious as hair loss or wrinkles crawling around our lips. But after 50, we may lose 1-2 percent of our muscles each year and along with it, our strength. If you find it harder and harder to lift your rollerboard into the storage compartment of the plane after 50, blame it on muscle loss. If a hill seems higher as you age, it is not due to the sinking of the earth; rather, your leg muscles have lost the strength to make the climb easy. And it gets worse. By 60, you will be losing 3 percent of your muscle each year (1). Add months of inactivity, for whatever reason, and the loss of muscle can accelerate as we saw with our friend.
The consequences of sarcopenia are like a perfect storm for hospitalization and even death. Balance is affected, making falls more likely. Bone strength depends in part on muscle mass; less muscle and more fragile bones may cause hip and back fractures from that fall. Difficulty in moving, even out of a chair, may lead to dependency on others for care, inability to leave the house without difficulty, social isolation, and even depression. And though we see the consequences of this among an older population who can no longer climb stairs, cross the street fast enough before the light changes, or who have trouble carrying packages, the process can start decades earlier. Recently, an acquaintance told me that her husband, who just turned 50, announced he was too old to exercise and was dropping his gym membership. Visions of wheelchairs danced in my head as I begged her to change her husband's mind. "But since he no longer does any competitive sports, now that a bad knee made him give up tennis, he doesn't see the need to maintain his fitness," she told me.
Alas, I suspect that his lack of interest or motivation to continue to exercise is not unique. Indeed, the idea of even starting to exercise after entering middle age and beyond may be as attractive as swimming with sharks. Yet current research is indicating that as muscle mass decreases, so also does muscle strength. And, if one suffers from obesity, diabetes, coronary heart disease and arthritis, the decrease in strength is even greater. What this means is that even if think your muscle mass is adequate, if you have any of these underlying medical conditions, your strength is much less than someone without these conditions (2). The good news from this research is that if you are not suffering from one of these conditions, your muscular strength is positively correlated with your muscle mass. Since A was healthy and did not suffer from any of these medical problems, if he takes the proper steps, he can regain his strength and muscle mass.
So how will he be able to do this? With the appropriate exercise and diet. Both are important alone but together have a much greater impact (3). Weight lifting or other types of resistance training that target muscle groups is the optimal way of stimulating muscle growth. If A lifts his body weight by repeatedly getting up from a chair, he will strengthen his thigh muscles. Lifting his body weight through stair climbing will do the same for other leg muscles groups as well. Using resistance bands or weights will probably be necessary to increase his upper body strength. Since he has years of experience working out in a gym, A knows what to do. Otherwise he might need to help of a trainer or physical therapist.
Eating sufficient protein is just as important as exercise. Body builders have known this forever. Walk into any store that sells nutritional products and your eye will be assaulted by enormous jars of muscle-building protein powders usually illustrated with a well-muscled man lifting a gazillion pounds over his head. Since most people who need to restore muscle mass and strength do not aspire to lifting 500-pound weights over their head while dressed in a micro bikini, they may not feel they need as much protein as advertised in these protein powders. For decades, it has been assumed that regardless of age, we all should be eating about 0.8 grams of protein per kilogram of body weight (3). So if A weighs 150 pounds. or approximately 68 kg, his protein intake should be 54 grams of protein a day (0.8 x 68).
But this may not be enough for our friend, as substantial muscle loss has already occurred. According to current studies, because he has lost so much muscle, A should be eating 1-1.2 grams of protein per kg of body weight and he should divide his protein consumption equally between three meals (4). If he eats 1/2 cup of cottage cheese for breakfast (13g protein), 4 ounces of tuna fish for lunch (30 g) and 4 ounces of steak for dinner (30 g), he will getting enough protein. A is fortunate; he has family and friends near by who will prepare and share such meals with him.
But many elderly (and not so elderly) get too little protein and too little exercise. The impact financially and socially of their potential muscle loss could be enormous. By 2020, more than 6 million Americans will be over the age of 85 and 55 million over 65 (5). The "frailty implosion" may be coming unless we begin now to pay attention to what we eat and how we move.
1. Rosenberg, I., "Sarcopenia: origins and clinical relevance," J Nutr 1997 vol 127)
2. Chen Lei, Nelson D, Zhao Y, et al, "Relationship between muscle mass and muscle strength, and the impact of comorbidities: a population-based, cross-sectional study of older adults in the United States," Geriatrics 2013, 13; 1271
3. Bicko, G, Tipton K, Klein S et al, "An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein," Am J Physiol. 1997; 273
4. Paddon-Jones, D, Rasmussen B. "Dietary protein recommendations and the prevention of sarcopenia," Curr Opin Clin Nutr Metab Care 2009, 12
5. Vincent, G., Velkoff, V. "The Next Four Decades, The Older Population in the United States 2010-2050." Current Population Reports 2010, Washington DC: U.S. Census Bureau
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